1. Field of the Invention
This invention relates to a gear support assembly for rotatably supporting a change speed gear train, and more particularly to a pair of support arms that rotatably support the free end portions of shaft members having meshing gears positioned thereon.
2. Description of the Prior Art
In press feeding operations it is known to feed a strip of stock material from a coil to the dies of the press for punching, stamping, cutting or the like of a preselected length of the material. The material is fed at a preselected linear speed from the coil in timed relation with the punching operation so that when the dies contact the material, the material is released from the feed mechanism so that movement of the material to the dies is interrupted. After the punching operation is completed, the feed mechanism advances another preselected length of the material to the dies. With this arrangement, the feeding of the material to the press is intermittent and coordinated with each downward stroke of the dies, so that prior to each downward stroke of the press, a new length of the material is in position for punching.
As disclosed in the April, 1976, publication of Metal Stamping by the article entitled "A Cam Feed . . . Next Step Forward in Pressroom Technology", it is known to utilize cam-type feeds for translating rotary motion of the punch press crankshaft to linear motion of the stock material. This is accomplished by drivingly connecting the feed roll of the feed mechanism through a change speed gear train and a drum-type cam to the drive shaft of the press. As disclosed in U.S. application Ser. No. 836,310 filed Sept. 26, 1977, the drum-type cam converts the continuous, uniform rotary motion of the crankshaft to non-continuous, step-by-step, intermittent rotary motion. The intermittent rotary motion from the drum-type cam is transmitted to a drive shaft of the feed mechanism. The drive shaft is drivingly connected through a change speed gear train to a driven shaft. The driven shaft is intermittently rotated at a preselected speed as determined by size and arrangement of the gears in the gear train. The driven shaft supports a feed roll and is intermittently rotated by the driven shaft at a preselected angular velocity to feed a preselected length of strip material to the press for each punching stroke. In order to rapidly change the length of the material fed to the punch press by the feed device, the gears in the gear train are changed to change the angular velocity between the drive and driven shafts. In this manner the angular velocity of the feed roll is changed which, in turn, results in a change in the length of the strip material fed to the press.
As disclosed in the above article, the drive shaft is drivingly connected through a change speed gear train to the driven shaft. The gear train includes a first drive gear nonrotatably connected to the drive shaft and a second driven gear nonrotatably connected to the driven shaft. A pair of intermediate gears drivingly connect the first drive gear to the second driven gear. The intermediate gears are rotatably supported on an intermediate shaft that is mounted on a support arm within the gear case. This arrangement permits the rapid change of sets of gears to thus change the feed length of the material fed to the press.
To insure accurate lengths of strip material being fed to the press, it is essential to maintain the same meshing relation between the gears in the gear train. Deflection of the shafts supporting the gears of the gear train especially the intermediate shafts adversely effects the accuracy of the feed device. In order to provide for rapid gear changes, it is desirable for the shafts supporting the gears to be rotatably supported and have free end portions extending into the gear case. The free end portions provide easy accessibility to the change speed gears and permit rapid change of the respective gears. The shafts having free end portions extending into the gear case are, however, subject to torsional deflection resulting from the torsion exerted by the input drive shaft. This is particularly true because of the intermittent drive imparted to the drive shaft by the cam drive mechanism. The torsional deflection tends to spread the gears apart and results in minor inaccuracies in the feeding operation.
There is a need for a support assembly to rigidly support the shaft end portions of all of the shafts within the gear case to prevent deflection of the shafts and maintain the same meshing relation between the gears on all of the shafts. The support assembly should not, however, materially increase the time required to change the gears in the gear train to provide a change in the feed length of the strip material.